Prognostic Meteorological Discussion
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FXAK02 KWNH 251950
PMDAK

ALASKA EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
350 PM EDT TUE APR 25 2017

VALID 12Z SAT APR 29 2017 - 12Z WED MAY 03 2017

AN UPPER RIDGE OF HIGH PRESSURE WILL ATTEMPT TO REMAIN THE MOST
PERSISTENT FEATURE DURING THE MEDIUM RANGE PERIOD. A DEVELOPING
RIDGE BASED OVER THE EASTERN PACIFIC WILL EXTEND UP THROUGH
WESTERN AND NWRN CANADA INTO CENTRAL AK. DESPITE A STRONG SYSTEM
SWEEPING INTO THE PANHANDLE AND BRITISH COLUMBIA ON SAT/SUN, AN
UPPER VORTEX/LARGE CYCLONE PROGRESSING FROM EASTERN RUSSIA TO THE
BERING SEA AND ALEUTIANS, AND THIS LARGE CIRCULATION POSSIBLY
INTERACTING WITH PAC SHORT WAVE SOUTH AND EAST OF THE ALEUTIANS.
IN ALL INSTANCES THE 500MB RIDGE EXTENDING INTO THE STATE HOLDS ON
OR RE-DEVELOPS. FOR THE SAT THROUGH MON PERIOD, WPC FOLLOWED A
SOLID BLEND BASED ON THE GFS AND ECMWF. THEN ON NEXT TUES AND WED,
WPC USED A LARGE PERCENTAGE OF THE GEFS/ECMWF/NAEFS MEANS TO
REMOVE SOME OF THE DETAIL DIFFERENCES. 12Z GFS 850MB TEMP
STANDARDIZED ANOMALIES ARE MOSTLY NEAR AVG OR SLIGHTLY ABOVE AVG.
MOST OF THE PRECIPITATION CHANCES WILL FOCUS RIGHT ALONG THE
IMMEDIATE SOUTHERN COASTAL AREAS FROM THE ALEUTIANS TO THE
SOUTHERN COAST TO THE AK PANHANDLE WITH LIGHT MOISTURE SPREADING
ACROSS THE SRN TIER OF THE STATE.


MUSHER

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